Why we should all be thankful for Nelson Mandela December 5th, 2013, by ksimpson
Just moments ago, I heard that one of the world’s greatest men has passed – thankfully in peace with his family surrounding him. I was born in South Africa; my family left shortly thereafter, but I continue to have ties to the country through relatives, and had the fortune of visiting there a year ago. […]
Fifty questions for Spamhaus, with our answers March 15th, 2013, by ksimpson
Ken Magill, who writes a weekly marketing blog called “The Magill Report”, recently solicited his readers to submit questions for Steve Linford, principle at Spamhaus. Ken’s readers sent in 51 questions, and I thought it would be fun to take a crack at answering them. Here goes: 1. How can Spamhaus work directly with legitimate […]
World’s largest spam sources are all hosting companies March 1st, 2013, by ksimpson
Over the past twelve months, there has been a dramatic shift in the world’s spam. Whereas twelve months ago, much of the world’s spam originated from botnet-controlled PCs on ISP networks, most of the world’s spam volume now originates from web hosting provider networks. This is an anachronism in many ways, because in the early […]
AOL accidentally rejects millions of messages October 16th, 2012, by ksimpson
AOL started rejecting connections instead of temp-failing them, under certain conditions. This has resulted in a major increase in non-delivery receipts worldwide.
How web hosting providers can battle fraudulent sign-ups October 2nd, 2012, by ksimpson
Spamhaus recently released an excellent guide for hosting providers describing how to avoid signing up fraudulent customers. In this blog post, we summarize Spamhaus’ recommendations.
What is fakemx.net and why are they temp failing me? September 26th, 2012, by ksimpson
In this post, we discuss what fakemx.net is, and why it’s generating temporary delivery failure notices in your mail server logs.
Why is Yahoo! temp failing my mail? September 25th, 2012, by ksimpson
In this article, we explain why Yahoo! sometimes temporarily fails connections to its mail servers with the error: “421 4.7.0 [TS01] Messages from 126.96.36.199 temporarily deferred due to user complaints – 188.8.131.52; see http://postmaster.yahoo.com/421-ts01.html”.
Why did I get “521 5.2.1 : (CON:B1) http://postmaster.info.aol.com/errors/554conb1.html?” September 24th, 2012, by ksimpson
In the first of a series of blog posts where we attempt to de-mystify the most common SMTP error codes, today we discuss the most popular error response from AOL: “521 5.2.1 : (CON:B1) http://postmaster.info.aol.com/errors/554conb1.html”.
Most popular SMTP responses – updated for August 2012 August 31st, 2012, by ksimpson
A summary of the top-50 most popular SMTP error responses, as collected at a major web hosting provider.
The leap second that killed the Internet (well, parts of it) July 3rd, 2012, by ksimpson
A bug in various software components caused a severe global outage of various services including the popular social news site Reddit.